Recent advances in the area of behavioral medicine have identified the Type A behavior pattern as a risk factor for coronary heart disease (CHD). The goal of the proposed investigation is to refine the concept of the Type A behavior pattern by identifying those specific behavioral subcomponents which are related to the greater prevalence of CHD found among individuals displaying this pattern. Two separate studies are proposed. As a first and necessary step, an investigation will be conducted to determine which behavioral subcomponents of the Type A behavior pattern can be reliably assessed. Reliability will be established in terms of adequate inter-rater agreement (i.e., scorer reliability) and temporal stability and consistency of response (i.e., test-retest reliability). These two approaches have not yet been systematically considered in previous studies of Type A behavior and CHD. After documenting that behavioral subcomponents can be reliably assessed, a second study is proposed to determine whether these behavioral subcomponents are differentially related to various manifestations of CHD, including angina pectoris, myocardial infarction and coronary atherosclerosis. By relating subcomponents of the Type A behavior pattern to coronary atherosclerosis determined in vivo by coronary angiography, the mechanisms by which Type A behavior contributes to increased risk of CHD may be further clarified. In addition, such knowledge could provide the basis for a more precise selection of behavioral targets for intervention programs designed to reduce the impact of the Type A behavior pattern upon risk of CHD.